Method for locating mobile station in distributed manner

Abstract

The invention relates to a method for locating a mobile station ( 1 ) by means of the mobile station ( 1 ) and a location service center (LSC) ( 5 ) in the mobile network by dynamically distributing the computing between these two. Preferably the mobile station ( 1 ) measures impulse responses of received bursts to determine time differences, and preprocesses measurement results. The location service center ( 5 ) performs the final processing. According to the invention, dummy bursts are also used in the locating process. The method also includes an automatic locating procedure activated in conjunction with an emergency call.

What is claimed is:  
     
       1. A method for locating a mobile station in a distributed manner using radio signals between the mobile station and mobile network, comprising steps: 
       obtaining differences of propagation times of signals propagating between the mobile station and other stations of the mobile network;  
       performing a locating process by location computing based on said differences of signal propagation time;  
       wherein said location computing includes steps of:  
       distributing the computing between a mobile network element and the mobile station by dividing the location computing into operation sequences by forming a first set of operation sequences and a second set of operation sequences separated by an execution boundary therebetween, said execution boundary being dynamically set between any location computing operations; and  
       carrying out said first set of operation sequences in a mobile station and carrying out said second set of operation sequences in the mobile network element.  
     
     
       2. The method of claim  1 , wherein the first set of operation sequences of locating process are carried out in the mobile station. 
     
     
       3. The method of claim  2 , wherein the first set of operation sequences of the locating process ore selected in the mobile station from among a set of operation sequences on the basis of a command from the mobile network. 
     
     
       4. The method of claim  2 , wherein the first set of operation sequences carried out in the mobile station are adapted to measurement results by determining parameters. 
     
     
       5. The method of claim  2 , wherein data processed in the mobile station by the first set of operation sequences are transferred to a location service center. 
     
     
       6. The method of claim  2 , wherein impulse responses are calculated in the mobile station from received location signals and those impulse responses are transferred to a location service center for further processing. 
     
     
       7. The method of claim  2 , wherein unprocessed measurement results are transferred from the mobile station to a location service center. 
     
     
       8. The method of claim  2 , wherein measurements and precalculation are carried out in the mobile station to decide whether measurement results will be sent from the mobile station to a location service center. 
     
     
       9. The method of claim  2 , wherein measurements and precalculation are carried out in the mobile station without carrying out the locating process proper to decide whether functions will be activated in the mobile station. 
     
     
       10. The method of claim  2 , wherein measurements and precalculation are carried out in the mobile station, and results of the measurements and the precalculation are compared with reference values to find out, without carrying out the locating process proper, whether the mobile station is located in a certain predetermined area. 
     
     
       11. The method of claim  1 , wherein the last operation sequences of locating process are computed in a location service center in the mobile network. 
     
     
       12. The method of claim  1 , wherein dummy bursts are used to determine timing. 
     
     
       13. The method of claim  1 , wherein locating is started automatically when a call is made to an emergency number. 
     
     
       14. The method of claim  1 , wherein the mobile station is located and the location is automatically indicated to an emergency center when an emergency function has been activated. 
     
     
       15. The method of claim  1 , wherein the mobile station is capable of transmitting an alarm to the mobile network, and is operative to transmit a recurrent message in the form of a request for a code which inhibits transmission of the alarm, wherein the mobile network waits for the recurrent message from the mobile station and if said message is missing, the alarm is generated. 
     
     
       16. The method of claim  1 , wherein the mobile station is capable of transmitting an alarm to the mobile network, and the mobile station decides when alarm conditions have been met. 
     
     
       17. A method for locating a mobile station in a distributed manner using radio signals between the mobile station and mobile network, comprising steps: 
       obtaining differences of propagation times of signals propagating between the mobile station and other stations of the mobile network;  
       performing a locating process by location computing based on said differences of signal propagation time:  
       wherein said location computing includes steps of:  
       distributing the computing between a mobile network element and the mobile station by dividing the location computing into operation sequences by forming a first set of operation sequences and a second set of operation sequences separated by an execution boundary therebetween, said execution boundary being dynamically set between any location computing operations: and  
       carrying out said first set of operation sequences in a mobile station and carrying out said second set of operation sequences in the mobile network element;  
       wherein the distribution of locating between the mobile network and the mobile station is dynamically changed by moving an operation sequence execution boundary.  
     
     
       18. The method of claim  17  wherein the moving of the operation sequence execution boundary is accomplished based on a computing capacity of the mobile station. 
     
     
       19. A method for locating a mobile station in a distributed manner using radio signals between the mobile station and mobile network, comprising steps: 
       obtaining differences of propagation times of signals propagating between the mobile station and other stations of the mobile network;  
       performing a locating process by location computing based on said differences of signal propagation time;  
       wherein said location computing includes steps of distributing the computing between a mobile network element and the mobile station by dividing the location computing into operation sequences; and  
       carrying out those operation sequences in the mobile network element and in the mobile station;  
       wherein, to determine time differences, different burst training sequences are compared by correlation with received signal, and an impulse response obtained as a result of that correlation is used for determining whether the training sequence is correct.